Narrative:Delta Air Lines flight 1086, a McDonnell Douglas MD-88, N909DL, was landing on runway 13 at New York-LaGuardia Airport (LGA) when it departed the left side of the runway, contacted the airport perimeter fence, and came to rest with the airplane's nose on an embankment next to Flushing Bay. The 2 pilots, 3 flight attendants, and 98 of the 127 passengers were not injured; the other 29 passengers received minor injuries. The airplane was substantially damaged. Flight 1086 was a regularly scheduled passenger flight from Atlanta-Hartsfield-Jackson Atlanta International Airport, Georgia, where it departed at 09:23 hours local time. Given the winter weather conditions at LaGuardia, the flight crew was concerned about the available landing distance on runway 13 (7003 ft / 2135 m). While en route to LGA they spent considerable time analyzing the airplane’s stopping performance.The flight crew also requested braking action reports about 45 and 35 minutes before landing, but none were available at those times because of runway snow clearing operations. The unavailability of braking actions reports and the uncertainty about the runway’s condition created some situational stress for the captain, who was the pilot flying.After runway 13 became available for arriving airplanes, the flight crews of two preceding airplanes (which landed on the runway about 16 and 8 minutes before the accident landing) reported good braking action on the runway, so the flight crew expected to see at least some of the runway’s surface after the airplane broke out of the clouds. However, the flight crew saw that the runway was covered with snow, which was inconsistent with their expectations based on the braking action reports and the snow clearing operations that had concluded less than 30 minutes before the airplane landed. The snowier-than-expected runway, along with the relatively short runway length and the presence of Flushing Bay directly off the departure end of the runway, most likely increased the captain’s concerns about his ability to stop the airplane within the available runway distance, which exacerbated his situational stress. The captain made a relatively aggressive reverse thrust input almost immediately after touchdown. Both pilots were aware that 1.3 EPR was the target setting for contaminated runways.As reverse thrust EPR was rapidly increasing, the captain’s attention was focused on other aspects of the landing, which included steering the airplane to counteract a slide to the left and ensuring that the spoilers had deployed, which was a necessary action for the autobrakes to engage. The maximum EPR values reached during the landing were 2.07 on the left engine and 1.91 on the right engine, which were much higher than the target setting of 1.3 EPR. These high EPR values likely resulted from a combination of the captain’s stress; his relatively aggressive reverse thrust input; and operational distractions, including the airplane’s continued slide to the left despite the captain’s efforts to steer it away from the snowbanks alongside the runway. All of these factors reduced the captain’s monitoring of EPR indications. The high EPR values caused rudder blanking, which occurs on MD-80 series airplanes when smooth airflow over the rudder is disrupted by high reverse thrust, and a subsequent loss of aerodynamic directional control. Although the captain stowed the thrust reversers and applied substantial right rudder, right nosewheel steering, and right manual braking, the airplane’s departure from the left side of the runway could not be avoided because directional control was regained too late to be effective.The airplane departed the left side of runway 13 about 3,000 feet from the approach end of the runway. The tracks were on a heading of about 10 degrees from the runway heading.About 4,100 feet from the approach end of the runway, the airplanes left wing initially struck the airport’s perimeter fence, which is located on top of the berm, and the airplane tracks turn back parallel with runway 13. About 5,000 feet from the approach end of the runway, the airplane came to rest with its nose over the berm. The left wing of the airplane destroyed about 940 feet of the perimeter fence.

Probable Cause:

PROBABLE CAUSE:The National Transportation Safety Board determines that the probable cause of this accident was the captain’s inability to maintain directional control of the airplane due to his application of excessive reverse thrust, which degraded the effectiveness of the rudder in controlling the airplane’s heading. Contributing to the accident were the captain’s (1) situational stress resultingfrom his concern about stopping performance and (2) attentional limitations due to the high workload during the landing, which prevented him from immediately recognizing the use of excessive reverse thrust.

Collaborate with Boeing and US operators of MD-80 series airplanes to (1) conduct a study to examine reverse thrust engine pressure ratio (EPR)-related operational data, procedures, and training and (2) identify industry-wide best practices that have been shown to be effective in reliably preventing EPR exceedances to mitigate the risks associated with rudder blanking.

Issued: 13-SEP-2016

To: FAA

A-16-21

Encourage US operators of MD-80 series airplanes to (1) implement the best practices identified in Safety Recommendation [1] and (2) participate in an industry-wide monitoring program to verify the continued effectiveness of those solutions over time.

Issued: 13-SEP-2016

To: FAA

A-16-22

Require operators of MD-80 series airplanes to revise operational procedures to include a callout when reverse thrust power exceeds 1.3 engine pressure ratio during landings on a contaminated runway.

Issued: 13-SEP-2016

To: FAA

A-16-23

Continue to work with industry to develop the technology to outfit transport-category airplanes with equipment and procedures to routinely calculate, record, and convey the airplane braking ability required and/or available to slow or stop the airplane during the landing roll.

Issued: 13-SEP-2016

To: FAA

A-16-24

If the systems described in Safety Recommendation [4] are shown to be technically and operationally feasible, work with operators and the system manufacturers to develop procedures that ensure that airplane-based braking ability results can be readily conveyed to, and easily interpreted by, arriving flight crews, airport operators, air traffic control personnel, and others with a safety need for this information.

Issued: 13-SEP-2016

To: FAA

A-16-25

Require 14 Code of Federal Regulations Part 121 operators to provide (1) guidance that instructs flight attendants to remain at their assigned exits and actively monitor exit availability in all non-normal situations in case an evacuation is necessary and (2) flight attendant training programs that include scenarios requiring crew coordination regarding active monitoring of exit availability and evacuating after a significant event that involves a loss of communications.

Issued: 13-SEP-2016

To: FAA

A-16-26

Develop best practices related to evacuation communication, coordination, and decision-making during emergencies through the establishment of an industry working group and then issue guidance for 14 Code of Federal Regulations Part 121 air carriers to use to improve flight and cabin crew performance during evacuations.

Issued: 13-SEP-2016

To: FAA

A-16-27

Clarify guidance to all 14 Code of Federal Regulations Part 121 air carriers to reinforce the importance of (1) having precise information about the number of passengers aboard an airplane, including lap-held children, and (2) making this information immediately available to emergency responders after an accident to facilitate timely search and rescue operations.

Issued: 13-SEP-2016

To: FAA

A-16-28

For airports certificated under 14 Code of Federal Regulations Part 139, direct airport certification safety inspectors to ensure, before or during the airports’ next scheduled annual inspection, that policies and procedures for friction measurement during winter operations are accurately and adequately described in the airports’ Airport Certification Manual and Snow and Ice Control Plan.

Issued: 13-SEP-2016

To: FAA

A-16-29

Revise Advisory Circular 150/5200-30D, Airport Field Condition Assessments and Winter Operations Safety, to provide more precise guidance regarding (1) the need to issue notices to airmen (NOTAM) in a timely manner and (2) the specific changes to runway surface conditions that would prompt the issuance of updated NOTAMs.

Issued: 13-SEP-2016

To: Boeing

A-16-30

Collaborate with the Federal Aviation Administration and US operators of MD-80 series airplanes to (1) conduct a study to examine reverse thrust engine pressure ratio (EPR)-related operational data, procedures, and training and (2) identify industry wide best practices that have been shown to be effective in reliably preventing EPR exceedances to mitigate the risks associated with rudder blanking

Issued: 13-SEP-2016

To: Boeing

A-16-31

Explore the possibility of incorporating an alert in MD-80 series airplanes to aid pilots in preventing engine pressure ratio exceedances.

Issued: 13-SEP-2016

To: US operators of MD-80 series airplanes

A-16-32

Collaborate with the Federal Aviation Administration and Boeing to (1) conduct a study to examine reverse thrust engine pressure ratio (EPR)-related operational data, procedures, and training and (2) identify industry-wide best practices that have been shown to be effective in reliably preventing EPR exceedances to mitigate the risks associated with rudder blanking.

Issued: 13-SEP-2016

To: Port Authority of New York and New Jersey

A-16-33

After consultation with the Federal Aviation Administration, clarify your policies regarding continuous friction measuring equipment use during winter operations and ensure that this information is included in the Airport Certification Manual and Snow and Ice Control Plan for each airport operated by the Port Authority.

A video posted by _veeestchic_ (@_veeestchic_) on Mar 5, 2015 at 8:25am PST

Map

This map shows the airport of departure and the intended destination of the flight. The line between the airports does not display the exact flight path. Distance from Atlanta Hartsfield-Jackson International Airport, GA to New York-La Guardia Airport, NY as the crow flies is 1216 km (760 miles).Accident location: Approximate; accuracy within a few kilometers.

This information is not presented as the Flight Safety Foundation or the Aviation Safety Network’s opinion as to the cause of the accident. It is preliminary and is based on the facts as they are known at this time.